Elastin is a critical connective tissue component imparting elastic properties to tissues. Although the structure and function of elastin, and the pathophysiological consequences of elastin degradation have received much attention, virtually nothing is known about processes which regulate the synthesis of elastin precursors or elastic fiber formation. Our data suggest that the extracellular matrix plays a key role in elastogenesis. Therefore, we propose to determine the affects of the extracellular matrix on elastin gene expression and elastic fiber formation, using bovine ligamentum nuchae as an in vitro model system. Ligament cells in culture will be exposed to isolated ligament extracellular matrix components and elastin synthesis and elastic fiber formation quantified by radioimmunoassays for soluble elastin and desmosine. Since elastin synthesis increases at a specific time of development, the role of extracellular matrix in induction of elastin synthesis will be determined. Cells from young ligament not producing elastin will be cultured with isolated extracellular matrix components from older ligament tissue where elastin production is maximal. The importance of direct cell-matrix contact in expression of the elastin phenotype, and the role of the extracellular microenvironment in preserving this phenotype will be investigated.